Caster

ABSTRACT

A caster for providing rolling support including a spring-loaded mount. The caster may be substantially concealed in the bottom edge of a hinged, swinging door, and generally located proximate to the free vertical edge of the door. An elongated spring plate is provided as a mount for a roller, causing the roller to accommodate variations in the floor surface, maintain contact with the floor, and support the door. The spring plate has a first portion adapted to be mounted to the bottom edge of a door, and a second portion depending from the first portion. An axle is mounted to the second portion, inside a hub that is mounted to the roller. The axle may be substantially parallel to the first portion of the spring plate. Single roller and double roller caster assemblies are provided.

BACKGROUND

The present invention relates to the field of casters for providingrolling support of objects, and more particularly concerns casters thatmay support swinging doors.

Casters are often used to provide rolling support for loads in a varietyof applications. In general, casters include a kingpin mounted to anobject, a bracket mounted to the kingpin, an axle mounted to thebracket, and a wheel or roller mounted to the axle. The bracket, axle,and wheel may swivel around the kingpin.

Casters are often used with doors, gates, or other similar hinged,swinging objects. Doors may sag at their free vertical edge, as hingesdo not always maintain the door in the originally installed alignment.Sagging becomes an increasingly significant issue for heavy and widedoors, resulting in a larger moment about the hinges. Casters aremounted to the door such that the roller is positioned between thebottom edge of the door and the floor, typically adjacent the freevertical edge of the door. The caster allows swinging movement of thedoor between closed and open positions while providing uplifting forceto place and maintain the door in position.

Some casters used for doors, gates, or the like, may also include a coilor leaf spring to allow vertical displacement of the roller relative tothe door to maintain contact with the floor, in case of variation inelevation of the floor relative to the door, as the door swings. Thecoil-type spring may be disposed around a telescoping kingpin or othersimilar arrangement. Alternatively, the spring may be leaf-type, beingwrapped around an axle on each side of a roller. With such arrangementsthe orientation of the axle is perpendicular to the longer dimension ofthe leaf spring, and the direction of the movement of the roller isaligned with the longer dimension of the leaf spring.

In some cases, for aesthetic reasons, it may be desirable to concealcasters within the doors. Concealed casters may be desirable in, forexample, heavy, wide, commercial doors in high-end offices, but may alsobe desirable elsewhere. Concealment requires that the caster fit withinthe thickness of a door. Most often the caster arrangement on doors isdisposed in plain view.

Accordingly, there exists a need for a new caster for a door. Ideally,the new caster may be substantially concealed in the door, and maymaintain contact with the floor over the extent of the door's movement.

SUMMARY

In accordance with an embodiment of the present invention, a caster fora door includes an elongated resilient spring plate including a firstportion and a second portion depending from the first portion. The firstportion of the plate is adapted to be mounted to the door. An axle ismounted to the second portion of the plate such that the axle issubstantially parallel to the first portion of the plate. A roller isoperatively connected, in other words mounted directly or indirectly, tothe axle, such that at least a part of the roller rotates. A hub may bedisposed between the axle and the roller. The roller may be aself-aligning bearing.

In accordance with another embodiment of the present invention, a casterfor a door includes an elongated resilient spring plate, a hub, an axle,and a roller. The elongated resilient spring plate includes a firstportion and a second portion depending from the first portion. The firstportion of the plate is adapted to be mounted to the door. The axle ismounted to the second portion of the plate such that the axle issubstantially parallel to the first portion of the plate, and the secondportion of the plate has a slot for receiving the axle. The slot issized for allowing the distance between the axle and the first portionof the plate to be adjusted. The axle comprises a threaded rod. The hubis mounted to the axle. The roller is mounted to the hub, and has asubstantially tight interference fit with the hub.

In accordance with another embodiment of the present invention, a doorincludes a door and a caster. The door includes a first major surfaceand a second major surface, and a hinged vertical edge, a free verticaledge, a top edge, and a bottom edge. The bottom edge is between andinterconnects the first major surface and the second major surface andhas a recessed surface defined between the first and second majorsurface of the door adjacent to the free vertical edge. The casterincludes an elongated resilient spring plate, an axle, and a roller. Theplate includes a first portion and a second portion depending from thefirst portion, wherein the first portion of the plate is mounted to thedoor in the recess such that the second portion is free from attachmentto the door. The axle is mounted to the second portion of the plate suchthat the axle is substantially parallel to the first portion of theplate. The roller is operatively connected to the axle, and at least aportion of the roller rotates.

In accordance with another embodiment of the present invention, a casterfor a door includes an elongated resilient spring plate including afirst portion and a second portion depending from the first portion, thefirst portion of the plate adapted to be mounted to the door. A bracketincludes a first portion and a second portion angularly extending fromthe first portion of the bracket, and the first portion of the bracketis mounted to the second portion of the plate. A hub has opposed endsand is mounted to the second portion of the bracket such that the hub issubstantially parallel to the first portion of the plate, and the endsof the hub define openings. An axle is disposed in the open ends of thehub. A roller is operatively connected to each axle, wherein at least apart of each roller rotates.

In accordance with another embodiment of the present invention, a casterfor a door includes an elongated resilient spring plate including afirst portion and a second portion depending from the first portion, thefirst portion of the plate adapted to be mounted to the door. A bracketincludes a first portion and a second portion angularly extending fromthe first portion of the bracket, and the first portion of the bracketis mounted to the second portion of the plate. A clamp includes arectangular portion and flanges along two opposed edges of the clamp.The clamp is adapted to be mounted to the first portion of the bracketand the second portion of the plate. The flanges of the clamp receivethe edges of the first portion of the bracket and the second portion ofthe plate. A hub has opposed ends and is mounted to the second portionof the bracket. The hub is substantially parallel to the first portionof the plate and the ends of the hub define threaded openings. An axleincludes at least one threaded rod, disposed in the threaded ends of thehub. Two rollers are provided, with one each mounted to the outside ofeach end of the hub and operatively connected to the axle. Each rollermay include a self-aligning bearing.

In accordance with another embodiment of the present invention, a doorincludes a door and a caster. The door includes a first major surfaceand a second major surface, and a hinged vertical edge, a free verticaledge, a top edge, and a bottom edge. The bottom edge is between andinterconnecting the first major surface and second major surface andhaving a recess defined between the first and second major surfacesadjacent to the free vertical edge. The caster includes an elongatedresilient spring plate including a first portion and a second portiondepending from the first portion. The first portion of the plate ismounted to the door in the recess such that the second portion is freefrom attachment to the door. A bracket includes a first portion and asecond portion angularly extending from the first portion of thebracket, with the first portion of the bracket mounted to the secondportion of the plate. A hub is mounted to the second portion of thebracket such that the hub is substantially parallel to the first portionof the plate. The ends of the hub define threaded openings. The axle ismounted to the open ends of the hub such that the axle is substantiallyparallel to the first portion of the plate. Two rollers are provided,with one each mounted to each end of the hub.

In accordance with another embodiment of the present invention, a methodof making a caster for a door includes providing an elongated resilientspring plate including a first portion and a second portion dependingfrom the first portion. The first portion of the plate is adapted to bemounted to the door. An axle is mounted to the second portion of theplate such that the axle is substantially parallel to the first portionof the plate, and a roller is operatively connected to the axle.

In accordance with another embodiment of the present invention, a methodof making a caster includes providing an elongated resilient springplate including a first portion and a second portion depending from thefirst portion. The first portion of the plate is adapted to be mountedto the door. A bracket is provided including a first portion and asecond portion angularly extending from the first portion of thebracket. The first portion of the bracket is mounted to the secondportion of the plate. A hub has a central portion and two opposed endswith each end defining threaded openings. The central portion of the hubis mounted to the second portion of the bracket. A roller is mounted toeach end of the hub. An axle is inserted through the roller and at leastinto the open ends of the hub. The axle is secured.

Features and advantages of the present invention will become moreapparent in light of the following detailed description of someembodiments thereof, as illustrated in the accompanying figures. As willbe realized, the invention is capable of modifications in variousrespects, all without departing from the invention. Accordingly, thedrawings and the description are to be regarded as illustrative innature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of a caster including asingle roller according to the present invention.

FIG. 2 is an exploded perspective view of the caster of FIG. 1.

FIG. 3 is a partially exposed elevation view of a door including thecaster of FIG. 1.

FIG. 4 is an exploded perspective view of a cover plate assembly for usewith an embodiment of a caster according to the present invention.

FIG. 5 is a perspective view of another embodiment of a caster includingtwo rollers according to the present invention.

FIG. 6 is an exploded perspective view of the caster of FIG. 5.

FIG. 7 is a partially exposed elevation view of a door including thecaster of FIG. 5.

DESCRIPTION

In the Figures herein, unique features receive unique referencenumerals, while features that are the same in more than one drawingreceive the same reference numerals throughout. Where a feature ismodified between figures or is modified only by a change in location, aletter may be added or changed after the feature reference numeral todistinguish that feature from a similar feature in a previous figure orthe same feature in an alternate location. Further, certain terms oforientation may be used, such as “horizontal,” “vertical,” “upper,”“lower,” “top,” “bottom,” “left,” “right,” “inside,” “outside,” “inner,”and “outer.” These terms are generally for convenience of reference, andshould be so understood unless a particular embodiment requiresotherwise. Where the terms “horizontal” and “vertical” are used, theyshould be understood to mean “approximately horizontal” and“approximately vertical,” respectively.

The scope of the invention is not intended to be limited by materialslisted herein, but may be carried out using any materials that allowconstruction and operation. Materials and dimensions depend on theparticular application. In general the materials of the components maybe metal, and selectively may be plastic, as known by one of ordinaryskill in the art.

Referring now to the drawings, an embodiment of a spring caster 20according to the present invention is shown in FIGS. 1 and 2. The caster20 includes a cantilever-type spring plate 22 with a horizontal portion24 having openings 26 a-26 d for mounting screws 28 a-28 d and washers30 a-30 d at one end and downturned vertical portion 34 at the otherend. Shims 32 a-32 c are provided for vertical adjustment relative tothe door during installation.

A roller assembly including a hub 36, a roller 38, and an axle 40 isprovided. The hub 36 has a smaller diameter portion 42 and a largerdiameter portion 44. The roller 38 includes an inner ring 46, an outerring 48, and ball bearings (not shown). The outer ring 48 rotatesrelative to the inner ring 46. The smaller diameter portion 42 of thehub 36 may fit in the inner ring 46 with a substantially tightinterference fit, such that there is no relative movement between thehub 36 and inner ring 46. The inner ring 46 comprises a self-aligningball bearing, including two raceways in which ball bearings aredisposed. The outer ring 48 has one raceway. The inside of the outerring raceway forms a spherical surface whose center coincides with thebearing center and has no defined path. The ball bearing design allowsmisalignment of the inner ring 46 and outer ring 48. An example suitableself-aligning bearings is Part #IT-0139A-0703, Crown Roller withSelf-Aligning Bearing by Intech Corporation of Closter, Ill. Otherbearings may be selected by one of ordinary skill in the art.

The axle 40 in this embodiment is a machine screw including a threadedend portion, as may be selected by one of ordinary skill in the art. Theaxle 40 may also be, for example, a threaded rod, with or withoutportions unthreaded, with or without a head, or a bolt. Where referenceis made to a threaded rod, it should be understood to include screws,bolts, rods with or without heads, rods omitting threads over someportion, or the like. The axle 40 may be aligned substantially parallelwith the longitudinal axis of the spring plate 22, with the direction ofmovement of the roller 38 perpendicular to the spring plate longitudinalaxis.

The axle 40 extends through the hub 36, roller 38, and a vertical slot50 in the vertical portion 34 of the spring plate 22. A nut 52 isthreaded onto the threaded end portion of the axle 40 for securing thehub 36 and roller 38 to the vertical portion of the plate 22. A starwasher 54 and lock washer 56 are provided to pre-load the assembly 20and to prevent turning and loosening of the axle 40. The slot 50 in thevertical portion 34 of the spring plate 22 allows vertical adjustment ofthe connection of the roller 38 relative to the horizontal portion ofthe spring plate 22. The nut 52 may be sized and shaped to help preventloosening by causing the nut to collide with the horizontal portion 24of the spring plate 22 when the nut tries to turn. For example, the nut52 may be a rectangular threaded block, as shown, or the like.

FIG. 3 shows a complete door and caster assembly 60, including a door 62and the embodiment of a caster 20 from FIGS. 1 and 2. A portion of theface of the door 62 is removed to expose the caster 20 and an end plateassembly 64. The caster assembly 20 is disposed in a recessed area 66formed in the bottom edge of the door 62. The horizontal portion 24 ofthe spring plate is secured to the door 62 with screws 28 a-28 d. Thespring plate 22 is cantilevered from the mounting screws 28 a-28 ddistal from the free vertical edge 70 of the door, and has a free end 72proximate to the free vertical edge of the door. Because the springplate 22 is flexible and resilient, the free end 72 of the spring plate22 may move up and down to support the door 62 and for the roller 38 tocontact the floor 74 as necessary. In the embodiment shown there arethree steps 76-78 to the recessed area, with the depth of each step fromthe bottom edge 80 of the door 62 increasing as the distance to the edge70 of the door 62 decreases. The stepped recessed area 66 provides spacefor the roller assembly. It should be understood that more or as few asno steps could be used by adjusting the number of shims 32 a-32 c,thickness of shims, or both.

An embodiment of an end plate assembly 64 is shown in FIG. 4 andincludes an end plate 90, two screws 92 a, 92 b that extend through twoopenings 94 a, 94 b, and two resilient electrometric strips 96 a, 96 b.The elastomeric strips 96 a, 96 b provide a load on the screws 92 a, 92b to keep them from loosening.

The end plate assembly 64 conceals the caster assembly 20 from the freevertical edge 70 of the door 62 if necessary, which is the case if thereis an opening on the free vertical edge 70. The entire caster assembly20 is substantially concealed between the faces of the door 62, exceptfor the portion of the roller 38 that extends beneath the bottom edge 80of the door. In many applications the roller 38 will not be visible fromthe viewing position of someone using the door 62, though the roller 38need not be concealed.

FIGS. 5 and 6 show another embodiment of a caster 100 according to thepresent invention. The caster 100 has a double roller assembly 102 thatmay be desirable when the load on the caster exceeds the capacity of thesingle roller caster 20 described above (FIGS. 1-3). The spring platearrangement of the double roller caster 100 is similar to that of thesingle roller caster 20. The parts of this embodiment of the caster 100which are identical to those of the caster 20 according to aboveembodiment are denoted by identical reference numbers and will not bedescribed in detail below.

An angle bracket 104 and a C-shaped clamp 106 are provided for securingthe double roller assembly 102 to the spring plate 22. The angle bracket104 has a vertical portion 108 and a horizontal portion 110, with anopening 112 a, 112 b through each portion. The vertical portion 108 ofthe bracket 104 and the vertical portion 34 of the spring plate 22 arereceived between the ends of the clamp 106. A screw 114 extends througha lock washer 116, a vertical slot 118 in the clamp 106, the opening 112a in the vertical portion 108 of the bracket 104, and the slottedopening 50 in the vertical portion 34 of the spring plate 22. Thevertical slots 50, 118 allow the double roller assembly 102 to beadjusted relative to the horizontal portion 24 of the spring plate 22. Anut 52 is threaded onto the end of the screw 114 for securing the anglebracket 104 and clamp 106 to the vertical portion 34 of the plate.

The double roller assembly 102 includes a hub 122, two rollers 38 a, 38b, and axles 124 a, 124 b. The hub 122 is double ended 124 a, 126 b, andhas a central portion 128 that includes a planar surface 130 having athreaded opening 132. The planar surface 132 is the mounting surface forthe horizontal portion 110 of the bracket 104. A screw 134 extendsthrough a lock washer 136 and the opening 112 b in the horizontalportion 110 of the bracket 104. The screw 134 and lock washer 136 mountthe spring plate 22 via the bracket 104 to the hub 122. The threadedopening 132 receives the screw 134 to secure the bracket 104. The ends126 a, 126 b, the central portion 128, or both, of the hub 122 may bethreaded and may accept two screws 124 a, 124 b with star washers 140 a,140 b and lock washers 142 a, 142 b. As with the hub 36 of the singleroller assembly, the ends 124 a, 124 b of the hub 126 of the doubleroller assembly 102 have a smaller diameter portion 144 a, 144 b and alarger diameter portion 146 a, 146 b. The smaller diameter portion 144a, 144 b of the ends 126 a, 126 b of the hub 122 may extend into theinner ring 46 a, 46 b of the roller 38 a, 38 b with a substantiallytight interference fit. The larger diameter portion 146 a, 146 b iscontiguous with the central portion 128 of the hub 122. The rollers 38a, 38 b may again be self-aligning bearings having an inner ring 46 a,46 b and an outer ring 48 a, 48 b, or alternatively other types ofbearings as selected by one of ordinary skill in the art. The axles 124a, 124 b pass through each end 126 a, 126 b of the hub 122 and eachroller 38 a, 38 b. Large washers 148 a, 148 b are provided between thehub 122 and rollers 38 a, 38 b to prevent wear of the rollers againstthe ends 126 a, 126 b of the hub 122. An alternative design may allowone bolt to pass through the entire hub 126 and make up the axle.

Like FIG. 3, FIG. 7 shows a complete door and caster assembly 150,including a door 62 and the embodiment of a caster 100 from FIGS. 5 and6. A portion of the face of the door 62 is removed to expose the caster100 and end plate assembly 64. The caster 100 is disposed in therecessed area 66 formed in the bottom edge of the door. As in theembodiment 60 previously described, because the spring plate 22 isflexible and resilient, the free end 72 of the spring plate 22 maydeflect and apply upward force to support the door 62. The entire casterassembly 100 is substantially concealed between the faces of the door62, except for a portion of the rollers 38 a, 38 b, which need not beconcealed and which extends beneath the bottom edge 80 of the door 62.

Specific embodiments of an invention are described herein. One ofordinary skill in the caster and door support arts will recognize thatthe invention has other applications in other environments. In fact,many embodiments and implementations are possible. For example, thecaster could be applied to articles other than doors. The caster of thepresent invention may have varying designs of mounts of the axles androllers to the spring plates. More than two rollers may be provided. Inaddition, the recitation “means for” is intended to evoke ameans-plus-function reading of an element in a claim, whereas, anyelements that do not specifically use the recitation “means for,” arenot intended to be read as means-plus-function elements, even if theyotherwise include the word “means.” The following claims are in no wayintended to limit the scope of the invention to the specific embodimentsdescribed.

1. A caster for a door, comprising: an elongated resilient spring plateincluding a first portion having a longitudinal axis and a secondportion depending from the first portion, the first portion of the plateadapted to be mounted to the door; an axle mounted to the second portionof the plate such that the axle is substantially parallel to thelongitudinal axis of the first portion of the plate; and a rolleroperatively connected to the axle, wherein at least a part of the rollerrotates.
 2. The caster of claim 1, wherein the second portion of theplate has a slot for receiving the axle wherein the slot is sized forallowing the distance between the axle and the first portion of theplate to be adjusted.
 3. The caster of claim 1, wherein the rollercomprises a self-aligning bearing.
 4. The caster of claim 1, wherein theaxle comprises a threaded rod, and further comprising a nut forthreading onto the threaded rod for securing the axle to the secondportion of the plate.
 5. A caster for a door, comprising: an elongatedresilient spring plate including a first portion and a second portiondepending from the first portion, the first portion of the plate adaptedto be mounted to the door; an axle mounted to the second portion of theplate such that the axle is substantially parallel to the first portionof the plate, wherein the axle comprises a threaded rod; a nut forthreading onto the threaded rod for securing the axle to the secondportion of the plate, wherein the nut is sized so that rotation of thenut when on the threaded rod causes the nut to abut the first portion ofthe plate to prevent nut rotation relative to the plate; and a rolleroperatively connected to the axle, wherein at least a part of the rollerrotates.
 6. The caster of claim 5, wherein the nut is rectangularlyshaped in the plane parallel to the second portion of the plate.
 7. Thecaster of claim 1, further comprising a hub disposed between the axleand the roller.
 8. The caster of claim 7, wherein the hub has a tightinterference fit with the roller.
 9. A caster for a door, comprising: anelongated resilient spring plate including a first portion having alongitudinal axis and a second portion depending from the first portion,the first portion of the plate adapted to be mounted to the door; anaxle mounted to the second portion of the plate such that the axle issubstantially parallel to the longitudinal axis of the first portion ofthe plate, wherein the second portion of the plate has a slot forreceiving the axle wherein the slot is sized for allowing the distancebetween the axle and the first portion of the plate to be adjusted andwherein the axle comprises a threaded rod; a hub mounted to the axle;and a roller mounted to the hub, wherein the roller has a substantiallytight interference fit with the hub.
 10. The caster of claim 9, whereinthe roller comprises a self-aligning bearing.
 11. A door comprising: afirst major surface and a second major surface, and a hinged verticaledge, a free vertical edge, a top edge, and a bottom edge, the bottomedge between and interconnecting the first major surface and the secondmajor surface and having a recess defined between the first and secondmajor surface of the door adjacent to the free vertical edge; and acaster including: an elongated resilient spring plate including a firstportion having a longitudinal axis and a second portion depending fromthe first portion, wherein the first portion of the plate is mounted tothe door in the recess such that the second portion of the spring plateis free from attachment to the door; an axle mounted to the secondportion of the plate such that the axle is substantially parallel to thelongitudinal axis of the first portion of the plate; and a rolleroperatively connected to the axle, wherein at least a part of the rollerrotates.
 12. The door of claim 11, wherein the caster is substantiallyconcealed within the recess in the bottom edge of the door.
 13. A casterfor a door, comprising: an elongated resilient spring plate including afirst portion having a longitudinal axis and a second portion dependingfrom the first portion, the first portion of the plate adapted to bemounted to the door; a bracket including a first portion and a secondportion angularly extending from the first portion of the bracket, thefirst portion of the bracket mounted to the second portion of the plate;a hub having opposed ends and mounted to the second portion of thebracket such that the hub is substantially parallel to the longitudinalaxis of the first portion of the plate and the ends of the hub defineopenings; two axles, one each disposed in each end of the hub in theopenings; and two rollers, one each operatively connected to each axleand including one or more parts, wherein at least a part of each rollerrotates.
 14. The caster of claim 13, wherein each axle comprises athreaded rod.
 15. A caster for a door, comprising: an elongatedresilient spring plate including a first portion and a second portiondepending from the first portion, the first portion of the plate adaptedto be mounted to the door; a bracket including a first portion and asecond portion angularly extending from the first portion of thebracket, the first portion of the bracket mounted to the second portionof the plate; a hub having opposed ends and mounted to the secondportion of the bracket such that the hub is substantially parallel tothe first portion of the plate, wherein the ends of the hub definethreaded openings; two axles, one each disposed in each end of the hubin the openings, wherein each axle comprises a threaded rod; and tworollers, one each operatively connected to each axle and including oneor more parts, wherein at least a part of each roller rotates.
 16. Thecaster of claim 13, wherein the hub has a substantially tightinterference fit with each roller.
 17. The caster of claim 13, whereinthe second portion of the plate has a slot for mounting the bracketwherein the slot is sized for allowing the distance between the axlesand the first portion of the plate to be adjusted.
 18. The caster ofclaim 13, wherein each roller comprises a self-aligning bearing.
 19. Thecaster of claim 13, further comprising a clamp including a rectangularplanar portion and flanges along two opposed edges of the clamp, theclamp adapted to be mounted to the first portion of the bracket and thesecond portion of the plate, wherein the flanges of the clamp receivethe edges of the first portion of the bracket and second portion of theplate.
 20. A caster for a door, comprising: an elongated resilientspring plate including a first portion and a second portion dependingfrom the first portion, the first portion of the plate adapted to bemounted to the door; a bracket including a first portion and a secondportion angularly extending from the first portion of the bracket, thefirst portion of the bracket mounted to the second portion of the plate;a clamp including a rectangular planar portion and flanges along twoopposed edges of the clamp, the clamp adapted to be mounted to the firstportion of the bracket and the second portion of the plate, wherein theflanges of the clamp receive the edges of the first portion of thebracket and second portion of the plate; a hub having opposed ends andmounted to the second portion of the bracket such that the hub issubstantially parallel to the first portion of the plate and the ends ofthe hub define threaded openings; an axle including at least onethreaded rod, disposed in the threaded ends of the hub; and two rollers,one each mounted to the outside of each end of the hub and operativelyconnected to the axle.
 21. The caster of claim 20, wherein each rollercomprises a self-aligning bearing.
 22. The caster of claim 20, whereinthe second portion of the plate has a slot for receiving the axlewherein the slot is sized for allowing the distance between the axle andthe first portion of the plate to be adjusted.
 23. A door comprising: adoor including a first major surface and a second major surface, and ahinged vertical edge, a free vertical edge, a top edge, and a bottomedge, the bottom edge between and interconnecting the first majorsurface and the second major surface and having a recess defined betweenthe first and second major surfaces adjacent to the free vertical edge;and a caster including: an elongated resilient spring plate including afirst portion and a second portion depending from the first portion,wherein the first portion of the plate is mounted to the door in therecess such that the second portion of the spring plate is free fromattachment to the door; a bracket including a first portion and a secondportion angularly extending from the first portion of the bracket, thefirst portion of the bracket mounted to the second portion of the plate;a hub having opposed ends mounted to the second portion of the bracketsuch that the hub is substantially parallel to the first portion of theplate and the ends of the hub define threaded openings; an axleincluding at least one threaded rod, disposed in the threaded ends ofthe hub; and two rollers, one each mounted to each end of the hub. 24.The door of claim 23, wherein each roller comprises a self-aligningbearing.
 25. The door of claim 23, wherein the caster is substantiallyconcealed by the door.
 26. A method of making a caster for a door,comprising: providing an elongated resilient spring plate including afirst portion having a longitudinal axis and a second portion dependingfrom the first portion, the first portion of the plate adapted to bemounted to the door; mounting an axle to the second portion of the platesuch that the axle is substantially parallel to the longitudinal axis ofthe first portion of the plate; and operatively connecting a roller tothe axle.
 27. The method of claim 26, further comprising mounting a hubbetween the axle and the roller.
 28. A method of making a caster,comprising: providing an elongated resilient spring plate including afirst portion and a second portion depending from the first portion, thefirst portion of the plate adapted to be mounted to the door; providinga bracket including a first portion and a second portion angularlyextending from the first portion of the bracket; mounting the firstportion of the bracket to the second portion of the plate; providing ahub having a central portion and two opposed ends, each end defining athreaded opening; mounting the central portion of the hub to the secondportion of the bracket; mounting a roller to each end of the hub;inserting an axle through each roller and into the hub; and securing theaxle.
 29. A caster for a door, comprising: an elongated resilient springplate including a first portion having a longitudinal axis and a secondportion depending from the first portion, the first portion of the plateadapted to be mounted to the door; a bracket including a first portionand a second portion angularly extending from the first portion of thebracket, the first portion of the bracket mounted to the second portionof the plate; a hub having opposed ends and mounted to the secondportion of the bracket such that the hub is substantially parallel tothe longitudinal axis of the first portion of the plate and the ends ofthe hub define openings; an axle disposed in the hub; and two rollersoperatively connected to the axle and including one or more parts,wherein at least a part of each roller rotates.
 30. The caster of claim29, wherein the axle comprises a bolt.
 31. The caster of claim 29,wherein each roller comprises a self-aligning bearing.
 32. The caster ofclaim 29, further comprising a clamp including a rectangular planarportion and flanges along two opposed edges of the clamp, the clampadapted to be mounted to the first portion of the bracket and the secondportion of the plate, wherein the flanges of the clamp receive the edgesof the first portion of the bracket and second portion of the plate.